A technique that protects a passenger room when high external force acts on an end bodyshell by collision is disclosed. For example, Patent Literature 1 discloses a technique that disposes a first end beam and a second end beam at an end portion in a longitudinal direction of an underframe to dispose an energy absorber and a sliding center sill between these first end beam and second end beam.
The sliding center sill includes a square-tubular-shaped first beam member fastened to the first end beam, and a square-tubular-shaped second beam member fastened to the second end beam. An end portion of this first beam member and an end portion of this second beam member are opposed one another and fitted to one another. At this fit portion, a plurality of mutually communicating holes are drilled. A plurality of coupling members (rivets and bolts) inserted into these plurality of holes combine the first beam member with the second beam member.
According to Patent Literature 1, when the first beam member collides with an oncoming car, the first beam member and the second beam member are displaced mutually in opposite directions to transmit a load to the coupling members. When the load equal to or more than a predetermined amount is transmitted to the coupling members, the coupling members are broken to allow the first end beam to move toward the second end beam. Thus, energy transmitted from the first end beam to the second end beam is absorbed by an energy absorbing member.